Thomas a



T. A. EDISON.

MAGNETIC SEPARATOR.

(No Model.)

No. 396,356 Patented Jan. 15, 1889.

N. PtTERS, Phota Lilhogrnpher. Wishingwn, D. K;

NITE TATES' FFICE.

THOMAS A. EDISON, OF LLElVELLYN PARK, NElV JERSEY, ASSIGNOR TO THEEDISON ORE MILLING COMPANY,

(LIMITED,) OF NEIV YORK, N. Y.

MAGN ETIC SEPARATOR.

SPECIFICATION forming part of Letters Patent No. 396,356, dated January15, 1889.

Application filed March 2 9, 1 8 8 8.

To call 2071 01221 it may concern.-

Be it known that l, THOMAS A. EDISON, a citizen of the United States,residing at Llewellyn Park, in the county of Essex and State of NewJersey, have invented a certain new and useful Improvement in MagneticSeparators, (Case No. 767,) of which the following is a specification.

My invention relates to apparatus for separating mingled magnetic andnon-magnetic materials of that character in which the mingled substancesin a finely-divided condition are caused to fall past the poles of amagnet, whereby the trajectory of the falling magnetic particles isaltered and they fall separately from the non-magnetic particles.

My-invention relates more particularly to the constructing andarrangement of the hopper used for discharging the material past themagnet-poles. lIeretofore V-shaped hoppers have been used for thispurpose; but I have found that in that case the normal direction offalling of the particles is not in a straight vertical line, but thatthey fall indifferent angular directions and spread out into anirregular mass, which makes it very difficult to act upon them by themagnets in the manner above mentioned. I remedy this by the employmentof a fiat-bottomed hopper provided with a narrow opening or openings atits middle part. I prefer to have a row of small holes across the bottomof the hopper, though I may have a single narrow slit. I prefer to makethe flat bottom of the hopper of thin sheet-brass. Vhen holes are used,the material leaving the hopper falls in a number of distinct verticalstreams, and these streams remain separated for a footor more below thehopper; but the particles being gradually spread apart by the effect ofthe air, the streams coalesce into a single wide thin mass, theparticles composing which are separated from one another, which makes iteasy for the magnet to act upon them, so that the direction of fallingof the magnetic particles is readily altered and they are readily andcompletely separated from those which are non-magnetic. lVhen thepulverized ore or other material to be acted upon is very fine, theholes must be very small. For one-hundred-mesh material the holes shouldbe three sixty-fourths of an serial No. 268,749. (No model.)

inch in diameter and one thirty-second of an inch apart. \Vhen the holesare so small, the particles do not pass readily through them, and toassist their discharge I prefer to provide means for putting the bottomplate of the hopper into vibration, whereby the particles of materialwill be vibrated or agitated,which will cause them to be dischargedfreely.

\Vhile, as stated, I prefer to provide the row of small holes in thebottom of the hopper, I may use in some cases a single narrow slit saythree sinty-fourths of an inch wide. In this case the particles remaincloser together and the magnetic separation may not be so perfect aswith the preferred form, for Where the particles are so close togethersome of the magnetic particles surrounding non-magnetic ones may carrythe latter down with them.

My invention is illustrated in'the accompanying drawings.

Figure 1 is a view principally in vertical section of magneticseparating apparatus embodying my invention. Fig. 2 illustrates thebottom of the hopper in the preferred form of the invention; Fig. 3, thebottom of the hopper in the form employing a narrow slit. Fig. 4 showsone way of vibrating the hopper. Fig. 5 shows another way, and Fig. 6 isa somewhat exaggerated view in section of a portion of the hopper in itspreferred form. 4

A represents a straight-sided box or hopper whose bottom is a thin metalplate, 13. This chamber is preferably placed at or near the top of aclosed chamber, 0. Below the 110pper is placed an electro-magnet, D, sothat the material falling from the hopper falls past the holes of saidmagnet. Below the magnet are placed two bins or receptacles,E and E.This general form of separating apparatus is shown and described in myprior patents, No. 228,329, dated June 1,1880,No. 248,432, dated October18, 1881, and No. 377,518, dated'February 7, 1888.

"It will be understood that when a stream 5 the receptacle E, while thenon-magnetic por-.

tion of the mixture falls vertically into receptacle E.

The bottom B of the hopper has either a row of small holes, CL a, acrossits middle part, as shown in Figs. 1, 2, l, and 6, or a single narrowslit, 1), as in Figs. 3 and 5.

In Figs. 2, 3, 4, and 5 the openings are shown at about their actualpreferred width in practice; but it will be understood that this isentirely out of proportion to the size shown for the hopperthat is, thehopper will be very much larger in proportion to the size of the holesthan it is shown, and there will be very many more holes in the row; andin Figs. 3 and 5 the slit Z) is shown at about its actual diameter, butit will of course be much longer proportionately than it is shown.

Fig. 6 shows approximately how the material falls from the holes. Inthis figure the holes are shown at about twice their preferred actualdiameter. The mingled material of which the hopper is kept full fallsthrough each hole in a straight stream, such streams being at firstdistinct from one another; but the particles gradually spread out, sothat at a distance of about a foot from the hopper the streams all uniteinto a wide thin sheet, the particles composing which are separated fromone another. At this point I place the magnet, which draws the magneticparticles aside from the rest, as illustrated in Fig. 1.

As stated, it is best in some cases to vibrate the bottom of the hopper.One way of doing this is shown in Figs. 1 and 4. F is a roller, which isrer olved by suitable power and which is covered with leather coatedwith rosin. Over the roller F are stretched a number of wires, 0 c,which are attached to the bottom plates of the hopper and whose otherends are rigidly secured, preferably adjustably, by screws cl. It willbe seen that the turning of the wheel under the wires will give themlongitudinal vibrations, which will give molecular vibrations to theplate of the hopper, and the vibrations thus given to the particles ofthe material will cause the same to fall freely through the openings.

. Another way of vibrating the hopper shown in Fig. 5. Several smallelectro-magnets, G G, have movable armatures mechanically connected withthe bottom of the hopper, and the circuits of these magnets are allcontrolled by a rotating circuit making and breaking wheel, so that saidarmatures are caused to vibrate and throw the plate into vibrations.

It is evident that a permanent magnet is the equivalent of aneleetro-magnet for the separating purposes of my invention. In myapplication, Case No. 339, filed August 25, 1882, Serial No. 7 0,288, isshown a different device for altering the trajectory of falling parti-'cles-viz., an electrostatically-charged' body for attracting suchparticles. It is evident that the hopper herein described is useful aswell with this kind of apparatus, and that the magnet and theelectrically-charged body are equivalents, so far as the presentinvention is concerned; and I wish it to be understood that under theexpression a magnet in the claims I include not only the electro-magnetshown and described, but also the above-mentioned equivalents thereof.

\Vhat I claim is 1. In amagnetic separator, the combination of a hopperhaving a flat bottom and an open in g therein, with a magnet below saidhopper for altering the trajectory of magnetic material fallingtherefrom, substantially as set forth.

2. In a magnetic separator, the combination of a hopper having verticalsides and a flat bottom with an opening therein, with a magnet belowsaid hopper for altering the trajectory of magnetic material fallingtherefrom, substantially as set forth.

In a magnetic separator, the combination of a hopper having a fiatbottom and a row of small holes therein, with a magnet below said hopperfor altering the trajectory of magnetic material fallin g therefrom,substantially as set forth.

4. In a magnetic separator, the combination of a hopper having a thinmetal bottom plate with an opening therein, with a magnet below saidhopper for altering the trajectory of magnetic material fallingtherefrom, substantially as set forth.

5. In a magnetic separator, the combination of a hopper having a thinmetal bottom-plate with a row of smallholes therein, with a magnet belowsaid hopper for altering the traj ectory of magnetic material fallingtherefrom, substantially as set forth.

6. In a magnetic separator, the combination, with a hopper having a flatbottom with an opening in it and means for vibrating it, of a magnetbelow said hopper for altering the trajectory of magnetic materialfalling therefrom, substantially as set forth.

7. In a magnetic separator, the combination, with a hopper having a flatbottom with a row of small holes in it and means for vibrating it, of amagnet below said hopper for altering the trajectory of magneticmaterial falling therefrom, substantially as set forth.

This specification signed and witnessed this 19th day of March, 1888.

TI-IOS. A. EDISON.

\Vitnesses:

\VILLIAM PELZER, A. W. KIDDLE.

